1. Field of the Invention
The present invention relates in general to enhancing the memory utilization efficiency of a digital data player such as an MP3 player, and more particularly to a digital data player, and a data processing method and a data storage medium for the same, in which information with a relatively small unit-capacity such as a voice or text is stored for reproduction in memory space remaining after files with relatively large unit-capacities such as a music file are assigned.
2. Description of the Prior Art
A digital data player such as an MP3 player is a new notional, portable digital audio reproduction device capable of readily downloading and reproducing desired music from a computer communication network using an audio data compression coding technique prescribed in MPEG1 Layer3.
The MP3 player reproduces audio from an MP3 file, which has a high compression rate as well as resulting in a sound quality indistinguishable from a compact disk (CD). In particular, with the development of a portable MP3 player, the supply of MP3 files is explosively increasing all over the world.
With reference to FIG. 1, there is shown in block form the construction of a conventional MP3 player. As shown in this drawing, the MP3 player includes a data storage medium 101 for storing an MP3 file (i.e., compressed according to an MPEG1 Layer3 coding technique), a decoder 102 for decoding an MP3 bit stream from the data storage medium 101 according to a predetermined decoding algorithm to output a sound signal in a digital form, and a digital/analog (D/A) converter 103 for converting the digital sound signal from the decoder 102 into an analog sound signal and for outputting the converted analog sound signal to a loudspeaker 104.
The operation of the conventional MP3 player with the abovementioned construction will hereinafter be described with reference to FIG. 2.
First, an MP3 file is stored in the data storage medium 101, which may typically be a flash memory or memory card. FIG. 2 illustrates an example of the data storage medium 101 in which MP3 files of M music tunes are stored. The data storage medium 101 provides an MP3 bit stream to the decoder 102, which then decodes the MP3 bit stream according to the predetermined decoding algorithm to output a digital sound signal. The D/A converter 103 converts the digital sound signal from the decoder 102 into an analog sound signal and outputs the converted analog sound signal to the loudspeaker 104.
Generally, in the MP3 player, one music tune occupies a 3xcx9c5-Mbyte memory area. As a result, even when the capacity to store music tunes has been filled, an idle area 101A exists in the data storage medium 101. The idle area 101A has a capacity of about 3 Mbytes when the music tune capacity of the data storage medium 101 has been filled. In this regard, the conventional MP3 player has a disadvantage in that the idle area in the high-cost memory 101 remaining after the music files are stored is left unused, resulting in inefficient resource utilization.
Therefore, the present invention has been made in view of the above problem, and it is an object of the present invention to provide a digital data player in which use is made of the idle area of a digital data storage medium.
It is another object of the present invention to provide a method for storing additional information in an idle area of a memory used for a digital data player.
It is yet another object of the present invention to provide a data storage medium for a digital data player which has a plurality of areas for storing digital data of different compression rates.
These and other objects are achieved by providing a digital player, comprising a decoder, having at least first and second decoding functions, identifying a type of digital data output from a data storage medium, selecting one of said first and second decoding functions based on said identified type, and decoding said output digital data using said selected decoding function and a converter converting said decoded digital data to analog.
These and other objects are further achieved by a digital player, comprising a first decoder, having a first decoding function, and decoding digital data according to said first decoding function, a second decoder, having a second decoding function, and decoding digital data according to said second decoding function, a controller identifying a type of digital data output from a data storage medium, selectively sending said output digital data to one of said first and second decoder based on said identified type, and a converter converting said decoded digital data output from said first and second decoders to analog.
These and other objects are still further achieved by a digital data recorder, comprising a first encoder encoding a first type of digital data at a first compression rate, and storing said encoded first type of digital data on a data storage medium, which stores digital data of a second type encoded at a second compression rate, said first compression rate higher than said second compression rate, and a selector, having at least a first and second input for said first type of digital data, and selectively outputting said first type of digital data received at one of said first and second inputs to said encoder.
These and other objects are also achieved by a data storage medium for a digital data player comprising a first compressed data region for storing a first digital data bit stream compressed according to a first compression algorithm, a second compressed data region for storing a second digital data bit stream compressed according to a second compression algorithm having a compression rate higher than that of said first compression algorithm, said second compressed data region forming one region of a specific area on said data storage medium, and a text data region for storing text data, said text data region forming another region of said specific area.
These and other objects are additionally achieved by a method of reproducing digital data, comprising identifying a type of digital data output from a data storage medium, selecting one of a first and second decoding function based on said identified type, decoding said output digital data using said selected decoding function, and converting said decoded digital data to analog.
These and other objects are further achieved a method of recording digital data, comprising selectively outputting a first type of digital data received at one of a first and second input, encoding said output first type of digital data at a first compression rate, storing said encoded first type of digital data on a data storage medium, which stores digital data of a second type encoded at a second compression rate, said first compression rate higher than said second compression rate.